What is Ozone?

Ozone is a highly reactive gas consisting of three oxygen atoms (O3). It is created when volatile organic compounds (VOC's) and nitrogen oxides (NOx) react with sunlight. At ground level, ozone is the main ingredient in smog, a health-threatening air pollutant. 

The Origin of Ozone Ingredients

The chemical components of ozone come from a variety of sources, many of which are man-made. By reducing the amounts of these chemicals that are released, we can reduce the formation of ground-level ozone.


The man-made sources of Volatile Organic Compounds (VOC's) include fossil fuel emissions released by industrial plants, gasoline engines (from large trucks to lawnmowers), manufacturing processes (like printing operations and painting), and numerous smaller sources (such as cleaning solutions).

The biogenic sources of Volatile Organic Compounds are essentially vegetation. Plants naturally release VOC’s, but the release can be triggered by activities like lawn mowing (the fresh "cut grass" smell is generated from VOC’s).

The second component of ozone is nitrogen oxides ( NOx). These emissions are a product of processes employing high temperature combustion. Power plants, industrial boilers, and motor vehicles are the principle NOx sources.

Good vs. Bad Ozone

Ozone must be considered by location—ozone in the stratosphere and ozone at ground level. Depending on where it is located, ozone can be either good or bad for one’s health. For several decades, scientists have been studying the depletion of the stratospheric ozone layer by chlorofluorocarbons (CFC's) and the damaging environmental effects of losing atmospheric ozone. This protective ozone layer is located several miles up in the atmosphere and shields the earth’s surface from intense ultraviolet radiation. Ozone that occurs at ground level, where we breathe and plants grow, however, is detrimental. Ground-level ozone, created by VOC's and NOx, is pollution. It does not replenish the atmospheric ozone layer and it is in no way good for the environment.

Good Up High

The ozone layer in the stratosphere occurs more than 10 miles above the surface of the earth. This thin, high altitude shield protects the earth from the sun’s ultraviolet rays. The ozone molecules block many of the sun’s harmful rays (UV-A and UV-B), and the thicker the layer of stratospheric ozone, the greater the protection. Scientists have found that chlorofluorocarbons (CFC's) deplete the ozone layer. CFC's are found in air conditioning and refrigerant systems, in industrial manufacturing processes like plastic foam, and in some cleaning solvents. CFC's were also previously used as propellants in aerosol spray products. The depletion of the ozone layer by chlorofluorocarbons (CFC's) diminishes the protection ozone provides. The depleted ozone layer allows too many ultraviolet rays down to the earth's surface, increasing the risk of skin cancer and cataracts in humans and damaging natural environments, especially harming sea life. Scientists even suspect that ozone depletion results in depressed immune systems. Ozone depletion also leads to a reduction in crop yield, an increase in ground-level smog, and a reduction in oxygen producing microorganisms.

Bad Down Low

Ozone that occurs at ground level, where people breathe, is a very serious issue. In West Michigan, ground-level ozone is a warm-weather problem which is caused when nitrogen oxides (NOx) and volatile organic compounds (VOC's) react with sunlight and create ozone pollution, or smog. Ground-level ozone can occur hundreds of miles from where the VOCs and nitrogen oxides are emitted. Therefore, it is not just a big city problem.

Health and Environmental Effects of Ground-Level Ozone

Ground-level ozone air pollution damages crops, forests, and materials such as rubber and plastics. Adverse health effects include eye irritation, decreased vision, increased asthma and chronic lung disease incidence, coughing, dizziness, nausea, and reduced heart and lung capacity. Children, the elderly, those with respiratory ailments, and people who exercise heavily are especially sensitive to ozone air pollution.

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